In-facepiece dust concentration is changed dozens of times in a matter of minutes due to changes of the size of the gaps between the mask and face. Source. A respirator is a device designed to protect the wearer from inhaling particulate matter, including airborne microrganisms, fumes, vapors, i.e. gases.
Why join Brainly? A community for students. Products of the neolithic culture Steel plows Boats with sails Domesticated dogs Wild figs. the answer would mostly likely be referring to things that actually were of use to the neolithic people and agriculture was the biggest thing making the answer steel plow. anonymous.
The two most important developments of the Pre-Pottery Neolithic B (PPNB) period are a) the domestication of animals, and b) the spread of food-producing communities in large numbers across the Middle East. The main animals domesticated in the PPNB period were sheep, goats, cattle, and pigs.